rpm gauge not working ?

[e30_ziraki]

hi i have a 89 325is my rpm gauge works sometimes then sometimes redlines but im acutally at like 2k rpm ? why is that how can i fix it

[jlevie]

That sounds like a bad tachometer.

[Gregs///M]

Your SI board batteries are probably dead. If you have never replaced them, I would start there before replacing anything else. You can check my signature for more details about SI boards and batteries.

If you need a replacement board, let me know asap, I have one left.

Greg